Battery Cut Off.

[Martin_mad]

Good afternoon,

I'm fitting a battery cut off switch to my 2018-19 420R.

I intend to place it on the engine bulkhead, passenger side. I have made a template.

Got the battery side pretty much sorted but I want to use the 4 smaller spade connections to prevent damage if the switch is broke whilst engine is running.

I have the correct resistor.

Is there a 420 guide/wiring diagram that I can use?

Specifically, I'm looking for the correct take off from the ignition switch.

Martin.

[Jonathan Kay]

Private Message sent.

Jonathan

[ChrisC]

The factory wiring diagram doesn't show the battery master switch install.  The obvious change is the brown loom +ve connections are relocated from the starter terminal to the master switch.  Ignition switch connections remain unchanged as far as I can see. 

[John Vine]

I intend to place it on the engine bulkhead, passenger side.

Will you be able to reach it when seated and strapped in?  Will someone outside the car be able to reach it (in an emergency or on track, for example)?

JV

[Martin_mad]

Thank you for your replies.

John, the main reason for fitting the switch is to reduce the parasitic drain on the battery (previous one lasted under 18 months) the added security is a bonus.

I do want to meet up with fellow club members and have a go at the odd hill climb and track day though.
Is it a requirement to have an accessible cut off switch fitted?

Please excuse my ignorance as this is all new to me. 

Martin.

[John Vine]

Ah, I'd assumed you were proposing an alternative location to the standard FIA battery master switch, which of course doubles up as a way to combat parasitic drain as well as act as an emergency cut-out.

AFAIK, the FIA switch is required only for competitive motorsport.  Plenty of 7s do trackdays without one.

JV

[BigCol]

There are plenty of diagrams on the web... such as the one below.

I did exactly what you're looking to do and basically diverted the big red cable from battery to starter via the switch and added the resistor bit but didn't bother with the ignition part as, like you, I wanted to simply avoid the parasitic drain rather than have a "proper" cut-off switch.

 

[John Vine]

Re #1:

Is there a reason you don't want to fit the standard FIA switch?  Cost, perhaps?

JV

[Martin_mad]

Many thanks, that's exactly what I was looking for.

Martin.

 

[Martin_mad]

This is the one I bought.

https://www.demon-tweeks.com/uk/lma-fia-battery-master-cut-out-switch-lma788/

Martin.

[Martin_mad]

Sorry, the link doesn't appear to work.

[Jonathan Kay]

Demon Tweeks: LMA FIA Battery Master Cut-Out Switch

[Martin_mad]

 
This is the one.

 

[John Vine]

Re #8:

If you're about to fit an FIA switch, complete with resistor, I'm puzzled why you wouldn't want to fit it in the usual position (driver's side screen stanchion) rather than the bulkhead?

JV

[Martin_mad]

JV,

thanks for your input I am now reconsidering placing the switch on the drivers side Stanton. I have sat in my drivers seat and there's no possible way I can reach the switch if located on the passengers side. That's with or without the harness on.

Martin.

[Martin_mad]

Thanks all for your help and many thanks Jonathan for the guides.

Martin.